There are many designs of mirrors that are used by all sorts of vehicles. Generally due to the manner that mirrors are designed and installed on vehicles the driver does not have a comprehensive view on either side of the vehicle.
Present mirrors on for example, automobiles do not provide total coverage of the viewing area on both sides of the automobile. The driver of a vehicle usually has a rear view mirror and conventional left and right side view mirrors on each side of the vehicle. There is a blind spot created for the driver when both his rear view mirror and side view mirrors are properly and conventionally adjusted. This “blind spot” prevents the driver from viewing a predetermined area behind and the side of his vehicle by the use of the rear view and side view mirrors. A driver checking the view from both the rear view and side view mirrors cannot see a vehicle, which is in an adjacent lane, in a “blind area” along side his vehicle.
Typically, the rear view mirror provides a viewing angle of about thirty degrees. This angle may, of course, vary somewhat, but thirty degrees is typical and any variations will not be greater than about plus or minus five degrees.
The rear view mirror gives a partial view of the adjoining lanes of traffic when it is correctly adjusted so that if a car in an adjacent lane is far enough behind, the driver will see the car in his rear view mirror.
The driver's side view mirror is normally tilted at an angle of about twenty degrees (plus or minus one or two degrees) to a line drawn at right angles to the longitudinal axis of the car, depending upon the position of the driver, the distance between his eyes, his height and position in the seat.
A driver to help him see towards the rear and along the side of his car, to cover the view of the adjacent lane, tilts the driver's side view mirror. In positioning the driver's side view mirror, the driver must maintain some rearward part of his vehicle in view in order to have some base or reference point to judge how far other cars are to the rear.
Therefore, with respect to the driver's side view mirror the field of view is determined by the angle of the mirror and a driver cannot see anything to the left of a line of sight of the driver's side view mirror.
A similar problem occurs with the passenger's side view mirror creating a blind spot on the right side of the line of sight defined by the right side mirror.
In jurisdictions where they drive on the right side of the road, for the right side blind spot a driver has to turn his head to his right to an angle of around 120 degrees in order to check the blind spot. For the left side blind spot a driver has to turn his head to at least 90 degrees in order to check the blind spot. This is reversed in countries where they drive on the left side of the road.
Various solutions have been attempted to minimize the blind spot and avoid the driver having to turn his head to check the blind spot. For example, proposed solutions range from providing a supplemental mirror placed at an angle to the rear view mirror (see U.S. Pat. No. 4,832,476) or two or more flat mirrors juxtaposed to give different angles of view (see U.S. Pat. No. 4,200,359 or U.S. Pat. No. 6,062,699) or small convex mirrors that are attached on the conventional automobile side mirrors that show the blind spots (see U.S. Pat. No. 3,104,274). With the convex mirrors, an object that one sees is closer than it appears. This makes these mirrors dangerous in the sense that if a driver miscalculates when he/she changes lanes, she/he may cause an accident.
Other solutions have proposed the use of one or are prisms. For example U.S. Pat. No. 5,245,479 relates to an automotive, side, rear view mirror accessory in the form of a small flat mirror or prism configured to be adhesively attached to the surface of a standard automotive side view mirror, in an effort to provide the user with a wider scope of vision with regard to the reflected image in the mirror.
The small flat mirror or prism is located at the outer edge, namely, on the outer, left edge for the driver's side, view mirror and on the outer, right edge of the side view mirror on the passenger's side. The prism mirror in this reference cannot be adjusted independently of the side view mirror to accommodate the sitting position of the driver.
The light is refracted upon entering the prism and then reflected through the same side by the flat mirror on which the prism is mounted or a reflective coating on the backside of the prism to permit a wider viewing angle. The two adjacent sides of the mirror prism are of unequal length and the prism is not receiving incident light at 90 to the left of the prism.
U.S. Pat. No. 5,594,594 describes a triangular prism mirror mounted above or below a conventional side view mirror to enable the driver to view the blind spot area without any distortion of vision. The triangular prism mirror unit has three plane surfaces, the rear surface being blocked. By blocking (coating) the rear surface of the prism, the image entering one of the front surfaces will appear on the other front surface. By having the prism mirror situated above the conventional one it looks awkward and bulky and not at all eye-pleasing. The blind spot mirror obstructs part of the view of the driver which is just above the conventional mirror and that means the driver cannot check far ahead distances.
U.S. Pat. No. Re. 30,673 discloses a composite mirror assembly adapted to be mounted adjacent the driver of a vehicle to enable the driver to view objects, as other vehicles, within an area normally hidden from view by conventional vehicle mirrors. An additional mirror is positioned at an angle with respect to the conventional side mirror. FIG. 4 of this patent shows a prism attached to the face of a conventional mirror. The prism has a viewing surface at an angle of about 12 to 20 degrees to the surface of the flat mirror. No two sides of the mirror prism are the same length. The prism deflects light onto the surface of flat mirror in an effort to provide a view of the blind spot. The incident angle (what the eye is looking at) is much smaller than the viewing angle. This does not help the driver because what and how much area of the blind spot the driver sees has to be equal of the viewing area of the blind spot if items are to remain undistorted. In addition, the prism mirror is attached (affixed) to the conventional mirror, that means that if the conventional mirror is not set properly you can't really see clearly the blind spot. This mirror prism is not independently adjusted to accommodate the driver.
Further, because of the way the blind spot mirror is placed on the conventional mirror, it is not protected from surrounding shadows, reflections and of the elements (rain, snow) at all times. In other words there are elements that do not inspire confidence of seeing clearly the blind spot at all times.
Other more sophisticated methods of eliminating the blind spot have been proposed with the use of radar and cameras.
Other problems associated with side view mirrors relates to the surface area of the mirror protruding beyond the exterior surface of the vehicle causing reduced fuel efficiency, aerodynamic noise and vulnerability to damage.
Numerous solutions have been proposed for low profile mirrors using various reflective and refractive devices so the image is presented inside the car. Passive systems such as those disclosed in U.S. Pat. Nos. 5,594,593; 5,617,245; 5,914,815 and 6,424,474 have been rejected in view of the high cost, no substantial improvement in viewing area over conventional side view mirrors, flare and secondary reflections.
There is a need for a comprehensive solution that permits viewing of the blind spot and has a low profile.